fix bulk warning spam (archiverjs#208)

lib/core.js

@@ -18,6 +18,10 @@ var Transform = require('readable-stream').Transform;
 
 var win32 = process.platform === 'win32';
 
+if (process._loggedBulkDeprecation === undefined) {
+  process._loggedBulkDeprecation = false;
+}
+
 /**
  * @constructor
  * @param {String} format The archive format to use.
@@ -60,8 +64,6 @@ var Archiver = function(format, options) {
   };
 
   this._streams = [];
-
-  this._loggedBulkDeprecation = false;
 };
 
 inherits(Archiver, Transform);
@@ -559,8 +561,8 @@ Archiver.prototype.append = function(source, data) {
  * @return {this}
  */
 Archiver.prototype.bulk = function(mappings) {
-  if (!this._loggedBulkDeprecation) {
-    this._loggedBulkDeprecation = true;
+  if (process._loggedBulkDeprecation === false) {
+    process._loggedBulkDeprecation = true;
     var warning = 'Archiver.bulk() deprecated since 0.21.0';
     if (typeof process !== 'undefined' && typeof process.emitWarning !== 'undefined') {
       process.emitWarning(warning, 'DeprecationWarning');
@@ -901,4 +903,4 @@ module.exports = Archiver;
  * when working with methods like `directory` or `glob`.
  * @property {fs.Stats} [stats] Sets the fs stat data for this entry allowing
  * for reduction of fs stat calls when stat data is already known.
- */
+ */